1. Field of the Invention
The invention concerns a barrier for blocking the passage of a vehicle, especially a vehicle attempting to crash through the barrier. The inventive barrier has a bollard post disposed to obstruct a vehicle path. The post is coupled to piercing bars or pikes that are normally kept in a compact stand-by state in a recessed housing bordering the vehicle path. The bars deploy pivotally when the vehicle strikes and pivots back the post. The bars or pikes impale the body of the vehicle and break away in an assembly together with the barrier post, to interfere with controlled or powered driving of the vehicle.
2. Prior Art
It is often desirable to prevent vehicles from passing along predetermined paths. A path may be large enough to admit vehicles or even structured as if intended to admit vehicles, such as a paved lane, but is obstructed due to some traffic control need. In connection with security interests, it may be desirable to prevent vehicles from passing along a path that is normally not intended for vehicle traffic, such as to prevent a vehicle from crashing through a perimeter or guard checkpoint or entrance to a public building.
For security reasons, many government and public buildings such as embassies, consulates, federal courthouses, historical sites and other perceived targets, have been equipped in recent years with barriers comprising heavy closely spaced obstructions such as concrete bollards, planter pots, etc. These barriers are intended to allow pedestrians to pass relatively freely between them, but to present relatively immovable obstructions to a speeding vehicle driven with the intent of crashing through, such as a car or truck containing explosives.
There are many varieties of such obstructions. Among the less aesthetic, large diameter pipes can be embedded part way in the ground or in cast concrete, in turn being filled with concrete to add more mass. Removable or movable arrangements are available that can be retracted into a telescopic base or temporarily lifted out. Solid concrete urn-shaped structures can be used for this purpose. Urns or box-shaped planters can be hollow and filled with soil and plantings for mass.
Certain entrances to spaces such as driveways to pay-parking lots, vehicle-prohibited pedestrian walkways on institutional grounds, generally have less imposing barrier emplacements. Relatively lightweight pipe-bollards, possibly mounted removably, are sufficient protection provided they are visible, because in such instances the operator of the vehicle to be blocked is interested in preventing any damage to the vehicle. In the case of a government building such as an embassy, the vehicle operator may be a suicide bomber. Thus, more substantial barrier structures are often considered appropriate.
One or more obstructions of some form are mounted to obstruct the path, such as a driveway having a width comparable to the width of one or a few vehicles. Two or more obstructions can be spaced laterally across a driveway or other path with lateral sidewall barriers. The obstructions are spaced from one another and from the sidewalls by a distance that is narrower than the width of a typical vehicle to be blocked (e.g., an automobile), while freely admitting pedestrians and perhaps smaller vehicles such as bicycles.
According to some techniques, a shock absorbing mechanism such as a heavy net coupled to tension damped cables can arrest the motion of a vehicle. In another technique, an advancing vehicle can be diverted into a dead-end side spur of one kind or another.
Very massive obstructions are more likely to function effectively as immovable masses to stop a determined attacker or a heavy vehicle than less massive obstructions suitable for lighter vehicles or attacks that are more tentative. Thus, the type and dimensions of an obstruction are dictated by interests such as the gravity of the danger and the size and speed of the expected attack. It is normally undesirable to provide such a substantial barrier that the public building or the like appears heavily fortified. It would be advantageous if public buildings, courthouses, historical sites and the like could appear open and readily accessible to the public. But these are the same sites that seem to be in the greatest danger of terrorist attack. Such sites are sometimes provided with imposing obstructions that are not only forbidding and unaesthetic, but they are expensive. Heavy construction equipment is needed to install or move them. Inadvertent damage (as opposed to deliberate attack) can occur and is expensive to repair. Some form of visually more attractive (or at least less forbidding) obstruction would be desirable, if it achieves comparable protection against attack.
Defensive obstructions against vehicles have been proposed for acute needs such as the entrance driveways for embassies, military checkpoints, border crossings and the like. In U.S. Pat. No. 5,026,203xe2x80x94Gorlov, a movable gate obstruction is provided to pierce laterally into the body of a vehicle advancing along a path, and is movable with advance of the vehicle to divert the vehicle laterally into a dead end siding. For authorized vehicles, the diverting mechanism can be rotated back and clear of the path.
A similar diversion path in U.S. Pat. No. 4,647,246xe2x80x94Brink et al. is arranged such that a trapdoor arrangement can drop away to cause an unauthorized vehicle to be diverted downwardly into a dead end path.
U.S. Pat. No. 5,704,730xe2x80x94Burton-Chambers has a barrier that comprises two pivotally attached members that can open to a maximum angle of 90 degrees. One of the members can be raised to vertical, leaving the other member below the ground surface in a housing box. If a vehicle should drive into the vertical member, the other member pivots up from the box. A ratchet non-return linkage is included. If a vehicle is driven into contact with the vertical member and continues to advance, the front of the vehicle is lifted from the ground. This arrangement seems directed to preventing inadvertent or slow speed advance, as opposed to thwarting an attempt to crash through a barrier.
A security gate that can be rotated to lay flush with the road surface is disclosed in U.S. Pat. No. 5,975,791xe2x80x94McCulloch. This gate has a beam pivoted on a central axis perpendicular to the direction of advance of the vehicle, with clearance underneath to rotate the beam through 360 degrees. The beam has vehicle-piercing points on both opposite ends, aimed in the same direction at right angles to the extension of the beam. The beam can be pivoted to a stowed-away horizontal position with both points facing downwardly, the upwardly facing side of the beam being flush with the road surface. The beam can be pivoted to a vertical defensive position. One point is then above ground, facing toward an oncoming vehicle. The other point is below ground. An impact with the raised end of the beam rotates the beam on the pivot and brings the other point up under the vehicle.
A gate as in McCulloch is theoretically similar to a tank obstruction in that it presents piercing structures that are intended to engage with the vehicle body to stop the vehicle at the obstruction. If built heavily, such an obstruction should stop a vehicle driven to crash through the barrier. However, determined crash could deform the apparatus and cause the vehicle to roll over the rotating beam even while suffering piercing impacts. It would be advantageous if possible to structure an arresting installation to better engage with a vehicle that is crashed and to use the kinetic energy of the vehicle to improve the extent to which the barrier structure engages with the vehicle while improving the chances that the vehicle will be disabled if crashed into the barrier at relatively high speed.
It is an object of the invention physically and psychologically to impede and deter crashing vehicle attacks on secured sites such as government buildings, populace areas and other potential terrorist targets.
It is an object to maximize the effective obstruction provided by a vehicle arresting installation. At the same time however, the installation is to interfere only minimally with the passage of authorized traffic and is to avoid adverse aesthetic aspects that often accompany security installations.
It is an aspect of the invention to provide a multi-part obstruction that employs relatively modest bollard post structures in conjunction with formidable vehicle arresting elements. The vehicle arresting elements are not concealed when retracted but preferably are held ready at the road surface. The arresting elements are deployed by the force of an attack, and unfold into a visually imposing array. The array comprises a set of pikes that are durably constructed, for example of angle iron stock. The array of pikes aggressively engages an attacking vehicle by using the force of the vehicle both to deploy the pikes and to achieve engagement as the vehicle drives onto the array.
According to a further object, the obstruction is arranged for defense against a range of attack speeds. For extreme attack speeds, a breakaway mounting permits the array of pikes to engage the attacking vehicle and to break free if the energy of the vehicle is sufficient to disengage the mounting, whereupon the array becomes lodged in and under the vehicle to interfere with the driver""s ability to continue to advance or to control the vehicle""s path.
The foregoing objects and other objects are met in an installation that obstructs movement of a car or similar vehicle along a path over a surface, such as along a road surface or driveway into a secure site. One or more standing bollards protrudes into the path from a support that can be recessed, flush with the road surface except for the bollard, which optionally is detachable. The support defines a pivot axis perpendicular to the path of the vehicle. If a vehicle strikes the bollard, the bollard pivots backward on the axis. Preferably, a clearance space is provided behind the axis. Elongated pike structures are coupled to the bollard and are pivoted up from the surface at an acute angle, to pierce and arrest the advancing vehicle. The pikes can be angle iron bars with barbed points. Preferably, several pikes are provided, and at least some are rotatable on the axis relative to the bollard, up to a maximum angle at which the pikes are angularly stopped relative to the bollard. The pikes stop at different angles. If a vehicle attempts to crash through the bollard, the piercing pikes are deployed in a bristling pike array that engages with the vehicle. The support can have a breakaway mounting at least for the axis, causing the pike array to roll under and progressively to impale the vehicle. This retards the vehicle and precludes effective control by the driver.